“So, what I mean is, you don’t NOT meet rich kids in Winnetka. I’m very lucky, coming from a great school. (She’s going to another, larger one in the fall: Columbia University, to study creative writing.) But I’ve certainly seen versions of these sorts of kids before.”

In “The Bling Ring,” opening next month, Chang plays the guileless party girl who indoctrinates the new kid at a Calabasas, Calif., high school into a life of drugs, drink and home burglaries targeting the rich and famous, magazine-cover types on the order of Paris Hilton, Megan Fox and Lindsay Lohan.

The movie opened the Cannes sidebar known as Un Certain Regard. It stars Emma Watson as the ringleader of the gang that couldn’t shop straight, though they enjoyed a pretty good spree while the Prada-nabbing and weirdly easy celebrity home break-ins lasted.

Chang won her choice supporting role while a New Trier junior, and while continuing her studies at the Actors Training Center in Wilmette. A taped audition led to a meeting with Coppola, the film’s casting director and a few other collaborators. That led to a second audition meeting, this one on the production's dime. Chang and company shot "The Bling Ring" last spring. Since then, she has acquired a manager and a multinationally powerful agency (ICM) and has already shot a second feature (“A Birder’s Guide to Everything,” co-starring Kodi Smit-McPhee and Ben Kingsley).

So here they are in Cannes, Chang and her mother, straight from a pre-festival getaway in Paris. Chang’s teachers, she says, have been “really great” about letting her take her homework away from home, while she’s been on the road either shooting or promoting motion pictures. As for her fellow students, “I’m happy that they’re excited about the movie coming out,” she says, referring to “The Bling Ring.” “I’m happy they’re not rude about it, or you know, putting me down about it. At least I haven’t heard anything like that.”

Coppola, Chang says, set a loose and creative atmosphere during filming and was keen on bringing out “an alluring quality, a sort of creepy friendliness” in Rebecca, so that the audience-identification figure, played by Chang’s fellow newcomer Israel Broussard, would have a plausible reason to fall in with this exotic crowd.

Now Chang’s career has a lot of possibilities in its suddenly spot-lit corner. For now, she says, eyeing Columbia in the fall, “I want to use things I learn about writing in my acting, and vice versa.” And with that, the “Bling Ring” co-star is done with her latest interview, this one conducted in the bar at the Martinez Hotel along the Croisette, with various handlers and publicists and a mom in tow.

CANNES, France — The class envy raging through F. Scott Fitzgerald’s “The Great Gatsby” helps to explain why teenage readers, usually assigned the book in school, fall under its spell. So sad about that doomed love, the kids sigh. Money can’t buy you the best things in life. But those mad Prohibition-era...